Daniel Ek, founder of Spotify, said he planned to build on its "above industry standard" click-through rates by allowing brands to buy ad space based on where users live and which tracks they listen to.

People getting wigged out about privacy issues in 4...3...2... Oh, who am I kidding - Spotify, like Google & Apple, can do no wrong in the eyes of their fans. Also, there's always the option of buying your way out of the ads with a subscription. Choice is good.

Will non-music related ads work in the all-music environment though? On that the jury is still out.

The COI, HMV, Nissan, Philips, Sainsbury's, Sony Pictures, Vodafone and Xbox are among the first brands to target Spotify's 250,000 UK users.

Dave Chase, head of music partnerships for Mindshare, said the start-up was rapidly heading for the mainstream. "We're at a point where it's becoming a more natural part of the conversation during client briefs. That's a good sign it's a sustainable model," he said.

Kevin Murphy, MD of Zed Media, which is about to launch a campaign on Spotify for Warner Music, said, "This is a very powerful direct-response add-on as it allows the attention-interest-desire-action model to be followed in minutes.

"As a direct-response medium for non-music brands, it will stand or fall on results," he added.